I'm returning to boarding after a few years away from it, and got a Futura 133 and Kombat 105 last year. Looking to get something smaller and would like some guidance / ideas...

The Kombat 105 seems really dialed in with a 6.5, good with a 5.0, and just not balanced when I've had to go down to a 4.5. My thought is that an 80L board makes sense for big wind days, but not sure if that's right, or what model would be the right direction.

I'm 6'3" 195 pounds (191 cm and 89 kg), hitting half my jibes (and quickly getting more as I get time on the water), and sail mostly on Cape Cod where it's flat or up to 4ft rolling chop in a big blow. Love speed, and I don't see a lot of freestyle in my future ;-) but do get a kick out of maneuvering around the big chop.

I use Kombat86 with 4.x-6.0 sails in big chop/swell and I think it will be a good choice for you, I mean the new Kode also (btw I'm 86 kg). It will have a good overlap with K105, but it won't take a 6.5 at your weight, crossover sail somewhere around 5.5 I guess.
You could go for a Kombat/Kode 80, but only if you are mostly interested in higher wind range with a 4.5 (or smaller). It will be uncomfortably sinky in holey winds, and it won't have that comfortable overlap with your 105 that a K86 would have.

I'm not sure what's your best bet, personally I don't mind a bit bigger gaps between boards, in order to cover wider range of conditions.